Fluorescent light tube fixtures have long been used in commercial applications due to their advantages over incandescent lighting. The most common commercial application for years were fixtures using three or four fluorescent bulbs or light tubes in 48 inch lengths. The typical fixtures housing these light tubes for these applications were generally made from numerous pieces of thin, flexible sheet metal assembled with many bendable flanges, screws and/or rivets. The manufacturing, assembly and service of these prior fixtures was time consuming and costly.
These prior fixtures were typically designed and assembled to accept only light tubes of certain a length, typically 48 inches, with a fixed number, commonly four or eight, and positioned in fixed locations in the fixture. These common dedicated prior fixtures were initially equipped and sold with all of the associated hardware, for example ballasts, wiring and sockets, for the predetermined type and number of light tubes. This inflexibility in design is disadvantageous to consumers both at the point of sale as well as during the service life of the light. Purchasers of new fixtures were constrained to purchase, for example, a four tube light fixture when only two or three light tubes were needed to illuminate a particular area. In this instance, one or two of the four tubes could be removed which is unsightly and due to the fixed location of the tubes, uneven illumination of the target area results. Likewise, if a change in the illumination was desired during the service life of the fixture, tubes would have to either be removed or if the new desired illumination exceeded the fixed number of tubes that the fixture could accommodate, a new fixture would need to be purchased.
Progression of fluorescent lighting tube technology has further introduced metric-length fluorescent tubes, for example T5 style tubes, which are about 45.8 inches as compared with the typical English-length, for example T8 style tubes, which are about 48 inches. Prior light fixtures that were designed to accept English-length cannot accept the shorter tubes limiting consumers' choices on tube selection. To accommodate the difference in length, separate conversion devices have been employed in an attempt to make up the difference in lengths between the types of tubes. These separate conversion devices or adaptors are disadvantageous as they require separate purchase and retrofitting into the existing fixtures, are relatively complex in design and add to the already numerous pieces of existing fixtures.
Due to the disadvantages in existing light fixture designs, there is a need for a light fixture that is universal and modular in its ability to accommodate the different types, numbers and positional locations of light tubes in one fixture. It is further advantageous for a light fixture to be both customizable at initial assembly to meet a purchasing customer's requirements and easily adaptable in the field to meet changing illumination or application requirements. It is further desirable to have a light fixture that is economic to manufacture, assemble and service throughout the life of the fixture.